1. Field of the Invention
The invention is directed to an improved hydraulic unit for an electronically controllable brake system of a vehicle.
2. Description of the Prior Art
A housing block of a hydraulic unit of the type with which this invention is concerned is already known, for instance from German Patent Disclosure DE 198 05 843 A1. This housing block has a plurality of mounting faces, to which an electric motor, for instance, for driving pump elements disposed in the housing block, or an electronic control unit for triggering magnet valves provided in the housing block, can be secured. The housing block is furthermore provided with connections for supplying it with pressure fluid and, in addition to the installation chambers for the aforementioned pump drive, the pump elements and the magnet valves, it has still further installation chambers for damping devices. These damping devices are disposed downstream of the pump elements in terms of circuitry, for damping pressure pulsations and the operating noises tripped by them.
In the known hydraulic unit, the installation chambers of the damping devices are fully integrated with the housing block and are furthermore disposed perpendicular to the installation chambers of the valves. This limits the possible volume of the damping devices and/or means that the hydraulic unit requires a relatively large installation space. Moreover, the pressure fluid conduits in the hydraulic unit that are required for hydraulically connecting the damping devices can be attained only with great effort in terms of production, and because of their length they further contribute to increasing the structural size of the hydraulic unit.
In another hydraulic unit of this generic type, disclosed in DE 199 58 194 A1, the damping devices coaxially adjoin the pump elements and are connected to the pressure buildup valves via pressure fluid conduits that extend radially or tangentially. This mode of construction has the same disadvantages described above. Especially the maximum possible volume of the damping devices is severely restricted, since the pump elements already occupy a substantial proportion of the possible length of the housing block in the direction of the longitudinal axes of the pump elements.